The Universally Conserved Residues Are Not Universally Required for Stable Protein Expression or Functions of Cryptochromes.

Universally conserved residues (UCRs) are invariable amino acids evolutionarily conserved among members of a protein family across diverse kingdoms of life. UCRs are considered important for stability and/or function of protein families, but it has not been experimentally examined systematically. Cryptochromes are photoreceptors in plants or light-independent components of the circadian clocks in mammals. We experimentally analyzed 51 UCRs of Arabidopsis cryptochrome 2 (CRY2) that are universally conserved in eukaryotic cryptochromes from Arabidopsis to human. Surprisingly, we found that UCRs required for stable protein expression of CRY2 in plants are not similarly required for stable protein expression of human hCRY1 in human cells. Moreover, 74% of the stably expressed CRY2 proteins mutated in UCRs retained wild-type-like activities for at least one photoresponses analyzed. Our finding suggests that the evolutionary mechanisms underlying conservation of UCRs or that distinguish UCRs from non-UCRs determining the same functions of individual cryptochromes remain to be investigated.

Monodisperse restricted access material with molecularly imprinted surface for selective solid-phase extraction of 17ß-estradiol from milk.

In this study, novel monodisperse restricted access media-molecularly imprinted polymers were successfully prepared by surface initiated reversible addition-fragmentation chain transfer polymerization using monodisperse crosslinked poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres as the carrier and acryloyl chloride-modified ß-cyclodextrin as the hydrophilic functional monomer. The surface morphology, protein exclusion, and adsorption properties of the molecularly imprinted polymers were investigated. The results show that the material has excellent monodispersity and hydrophilicity, and simultaneously exhibit high adsorption capacity, fast binding kinetics, high selectivity, and significant thermal stability. The molecularly imprinted polymers as dispersive solid-phase extraction adsorbent combined with reversed-phase high-performance liquid chromatography was used to selectively enrich, separate, and analyze trace 17ß-estradiol in milk samples. The recovery of 17ß-estradiol is 88-95% with relative standard deviation of <4%, and the limits of detection and quantification of this method are 2.08 and 9.29 µg/L, respectively. The novel restricted access media-molecularly imprinted polymer adsorbents provide an effective method for the selective extraction and detection of 17ß-estradiol directly from complex samples.

Molecularly imprinted polymer coating on metal-organic frameworks for solid-phase extraction of fluoroquinolones from water.

In this work, a novel surface molecularly imprinted polymer with high adsorption capacity, high adsorption rate, and high selectivity for fluoroquinolones was prepared on the surface of UiO-66-NH2 , which is a kind of metal-organic framework. The surface morphology and adsorption properties of this molecularly imprinted polymer were investigated. The maximum adsorption capacity was 99.19 mg/g, and adsorption equilibrium was achieved within 65 s. Combined with reversed-phase high-performance liquid chromatography, the molecularly imprinted polymer was used to selectively enrich, separate and analyze fluoroquinolones present in lake water. The results showed that the recoveries of the four fluoroquinolones were 92.6-100.5%, and the relative standard deviations were 2.9-6.4% (n = 3). The novel molecularly imprinted polymer is an excellent adsorbent and has broad application prospects in the enrichment and separation of trace analytes in complex samples.

Characterization and function of GSK3ß from Litopenaeus vannamei in WSSV infection.

GSK3ß, a serine/threonine protein kinase, is a crucial regulator in several signaling pathway and plays a vital role in multiple cellular processes including cell proliferation, growth, apoptosis and immune response. In this study, a GSK3ß homolog from L. vannamei, designed as LvGSK3ß, was characterized. Sequence analysis showed that LvGSK3ß possessed a highly similarity with GSK3ß from other species, which contained a catalytic domain and serine/threonine phosphorylation sites. To analyze the role of LvGSK3ß in the process of white spot syndrome virus (WSSV) infection, real-time quantitative PCR and western blot assays were performed. The results showed that the transcription and expression levels of LvGSK3ß were inhibited upon WSSV challenge, accompanied with down-regulated phosphorylation levels. When LvGSK3ß was silenced, the transcription of WSSV gene ie1 was inhibited, and the apoptosis of hemocytes induced by WSSV was up-regulated remarkably as well. In addition, inactivation of LvGSK3ß could also depress virus infection that further validated the results. Conclusively, LvGSK3ß was an important protein for shrimp immunomodulation, and shrimp might promote the apoptosis to restrain WSSV infection by inhibition of LvGSK3ß. The study will be helpful for understanding the molecular mechanism of host-virus interaction.

RNA-based translation activators for targeted gene upregulation.

Technologies capable of programmable translation activation offer strategies to develop therapeutics for diseases caused by insufficient gene expression. Here, we present "translation-activating RNAs" (taRNAs), a bifunctional RNA-based molecular technology that binds to a specific mRNA of interest and directly upregulates its translation. taRNAs are constructed from a variety of viral or mammalian RNA internal ribosome entry sites (IRESs) and upregulate translation for a suite of target mRNAs. We minimize the taRNA scaffold to 94 nucleotides, identify two translation initiation factor proteins responsible for taRNA activity, and validate the technology by amplifying SYNGAP1 expression, a haploinsufficiency disease target, in patient-derived cells. Finally, taRNAs are suitable for delivery as RNA molecules by lipid nanoparticles (LNPs) to cell lines, primary neurons, and mouse liver in vivo. taRNAs provide a general and compact nucleic acid-based technology to upregulate protein production from endogenous mRNAs, and may open up possibilities for therapeutic RNA research.

Development of Mild Chemical Catalysis Conditions for m1A-to-m6A Rearrangement on RNA.

The conversion of N1-methyladenosine (m1A) to N6-methyladenosine (m6A) on RNA is an important step for both allowing efficient reverse transcription read-though for sequencing analysis and mapping modifications in the transcriptome. Enzymatic transformation is often used, but the efficiency of the removal can depend on local sequence context. Chemical conversion through the application of the Dimroth rearrangement, in which m1A rearranges into m6A under heat and alkaline conditions, is an alternative, but the required alkaline conditions result in significant RNA degradation by hydrolysis of the phosphodiester backbone. Here, we report novel, mild pH conditions that catalyze m1A-to-m6A arrangement using 4-nitrothiophenol as a catalyst. We demonstrate the efficient rearrangement in mononucleosides, synthetic RNA oligonucleotides, and RNAs isolated from human cell lines, thereby validating a new approach for converting m1A-to-m6A in RNA samples for sequencing analyses.

Programmable technologies to manipulate gene expression at the RNA level.

RNA has long been an enticing therapeutic target, but is now garnering increased attention, largely driven by clinical successes of RNA interference-based drugs. While gene knockdown by well-established RNA interference- and other oligonucleotide-based strategies continues to advance in the clinic, the repertoire of targetable effectors capable of altering gene expression at the RNA level is also rapidly expanding. In this review, we focus on several recently developed bifunctional molecular technologies that both interact with and act upon a target RNA. These new approaches for programmable RNA knockdown, editing, splicing, translation, and chemical modifications stand to provide impactful new modalities for therapeutic development in the coming decades.

Preparation of monodisperse, restricted-access, media-molecularly imprinted polymers using bi-functional monomers for solid-phase extraction of sarafloxacin from complex samples.

Monodisperse restricted-access media bi-functional monomers with molecularly imprinted polymers (RAM-MIPs) were constructed using surface-initiated atom transfer radical polymerization. They were used as solid-phase extraction (SPE) adsorbents to enrich sarafloxacin (SAR) residues from egg samples, and influences on their performance were investigated. Optimum synthesis of RAM-MIPs was achieved by combining a bi-functional monomer (4-vinylpyridine-co-methacrylic acid, 1:3) with an 8:1:32:8 ratio of a template molecule, cross-linker, and restricted-access functional monomer. The SAR imprinting factor of RAM-MIPs was 6.05 and the selectivity coefficient between SAR and other fluoroquinolones was 1.86-2.64. Compared with traditional MIPs, the RAM-MIPs showed better SAR enrichment and selectivity during extraction of a complex protein-containing solution. Empty SPE cartridges were filled with RAM-MIP microspheres as SPE adsorbents. The limit of quantitation for SAR was 4.23 ng g-1 (signal-to-noise ratio = 10) and the mean SAR recovery from spiked egg samples was 94.0-101.3%. Intra-day and inter-day relative standard deviations were 1.1-9% and 1.5-3.3%, respectively.

Chlorine isotope analysis of polychlorinated organic pollutants using gas chromatography-high resolution mass spectrometry and evaluation of isotope ratio calculation schemes by experiment and numerical simulation.

Compound-specific isotope analysis of chlorine (CSIA-Cl) is a practicable and high-performance approach for revelation of transformation processes and source identification of chlorinated organic pollutants. This study conducted CSIA-Cl for typical polychlorinated organic pollutants using gas chromatography-high resolution mass spectrometry (GCHRMS) with an alternate injection mode using perchloroethylene (PCE) and trichloroethylene (TCE) as model analytes. PCE and TCE standards from two manufacturers were employed for method development, and chlorine isotope ratio calculation schemes were evaluated by experiment and numerical simulation. The achieved precision (standard deviation of isotope ratios) was up to 0.21‰ for PCE and 0.43‰ for TCE. The limits of detection for CSIA-Cl of were 0.05 µg/mL (0.05 ng on column), and the linearities were 0.05-1 µg/mL. Two isotope ratio calculation schemes, i.e., one using complete molecular isotopologues and another using the first pair of neighboring chlorine isotopologues of each analyte, were evaluated in terms of accuracy and precision. The complete-isotopologue scheme showed evidently higher precision and was more competent to reflect trueness than the isotopologue-pair scheme and the two schemes could present completely different outcomes. The method has been successfully applied to PCE and TCE reagents from different suppliers, a trichloromethane reagent, and a plastic material. The relative isotope ratio variations (Δ37Cl) of PCE and TCE in the reagents and plastic material were from -1.84±0.7‰ to 15.12±0.85‰. The analytes from different sources could mostly be discerned from each other by chlorine isotope ratios. This study will be conducive to transformation process elucidation and source identification of for PCE and TCE, and facilitate CSIA-Cl using GC-MS for more polychlorinated organic pollutants, particularly in selection and optimization of isotope ratio calculation schemes.

Synthesis of monodisperse magnetic restricted microspheres for recognition of thiamphenicol in milk.

Taking thiamphenicol as the research object, a new type of magnetic restricted access molecularly imprinted polymer (RAM-MMIP) with specific recognition was prepared by a one-step swelling method. The polymer microspheres were characterized and analyzed by scanning electron microscopy, X-ray diffraction, elemental analysis, contact angle measurement and vibrating sample magnetometry. When the ratio of template molecule, functional monomer and cross linking agent was 1 : 4 : 8, the adsorption capacity reached the maximum. Under these conditions, RAM-MIP magnetic solid phase extraction (M-SPE) was combined with HPLC to analyze thiamphenicol in milk samples. Satisfactory linear correlation (R 2 > 0.9977), good detection limit (LOD: 10.4 µg L-1), high recovery rate (96.5-101.1%), and relative standard deviation (RSD: 2.8-3.8%) were obtained. Therefore, our synthesized material can be used for the analysis of TAP in complex milk samples, and has broad application value.

Preparation of high-capacity magnetic polystyrene sulfonate sodium material based on SI-ATRP method and its adsorption property research for sulfonamide antibiotics.

A novel polystyrene sulfonate sodium (PSS) magnetic material was prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The starting materials were brominated magnetic material as the carrier and macroinitiator, sodium styrene sulfonate (NaSS) as the monomer, and cuprous bromide/2,2'-dipyridyl as the catalyst system. The PSS material was characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis, transmission electron microscope (TEM), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and a vibrating sample magnetometer (VSM). The adsorption properties of the material were then investigated on sulfa antibiotics. The kinetic and thermodynamic parameters were determined in adsorption of sulfamethazine (the smallest molecular-weight sulfonamide). The adsorption amount of sulfamerazine free acid (SMR) was found to increase with the initial concentration and temperature of SMR in solution. The adsorption effect was maximized at an initial concentration of 0.6 mmol/L. The static saturation adsorption capacity of the material was 33.53 mg/g, Langmuir and Freundlich equations exhibited good fit. The thermodynamic equilibrium equation is calculated as ΔG < 0, ΔH = 38.29 kJ/mol, ΔS > 0, which proves that the adsorption process is a process of spontaneous, endothermic and entropy increase. Kinetic studies show that the quasi-second-order kinetic equation can better fit the kinetic experimental results, which is consistent with the quasi-second-order kinetic model. The experimental results of kinetic studies were well fitted to a quasi-second-order kinetic equation. High performance liquid chromatography (HPLC) of an actual milk sample treated by the PSS magnetic material confirmed the strong adsorption of SMR from milk.

Restricted access magnetic imprinted microspheres for directly selective extraction of tetracycline veterinary drugs from complex samples.

A novel restricted access media-magnetic molecularly imprinted polymers (RAM-MMIPs) was prepared as magnetic-solid phase extraction (M-SPE) material for tetracyclines (TCs). The RAM-MMIPs can not only specifically adsorb target molecules in samples, but also effectively eliminate the interference of protein macromolecules. The protein exclusion rate is 99.4%. Besides, RAM-MMIPs have a uniform imprinted and hydrophilic layer (600 nm), rapid binding kinetic (35 min), high selectivity and larger adsorption capacity. The M-SPE was coupled with HPLC/UV to extract TCs from untreated milk and egg samples, and several major factors affecting M-SPE efficiency were optimized. Under optimized conditions, the developed method achieved good linearity (R2>0.9989), lower limits of detection (LOD) and higher recoveries of TCs. For milk samples, the LOD is 1.03-1.31 µg L-1 and the recovery is 86.7% to 98.6% with relative standard deviation (RSD) of 1.4-5.7%. For the egg samples, the LOD, recovery and RSD are 2.21-2.67 µg L-1, 84.2-96.5% and 1.7-5.9%, respectively. Consequently, this work provides an improved strategy for the selective extraction and detection of target molecules directly from complex samples with proteins.

Restricted access media-imprinted nanomaterials based on a metal-organic framework for highly selective extraction of fluoroquinolones in milk and river water.

A new type of restricted access media-imprinted nanomaterials (RAM-MIPs) were successfully prepared on the surface of metal-organic framework by reversible addition fragmentation chain transfer polymerization technology. Then it was applied as a dispersed solid phase extraction (DSPE) material in analysis of fluoroquinolones (ofloxacin, pefloxacin, norfloxacin, enrofloxacin and gatifloxacin) in untreated milk and river water by HPLC-UV detection. The resulted material has a good binding amounts (60.81 mg g-1), rapid binding kinetic (15 min) and satisfactory selectivity as well as has a good ability to eliminate matrix interference. Several major factors affecting DSPE efficiency, pH of sample solution, dosage of RAM-MIPs, adsorption time and volume ratios of elution solvent were primarily optimized. In optimization conditions, RAM-MIPs-DSPE was combined with HPLC-UV to enrich fluoroquinolones in untreated milk and river water, achieving satisfactory linear correlation (R2 > 0.9988), good limits of detection (LOD, 1.02-3.15 µg L-1 for milk and 0.93-2.87 µg L-1 for river water) and better recoveries (80.7-103.5% and 85.1-105.9% with relative standard deviation (RSD) of not higher than 5.3% and 4.7% for milk and river water samples, respectively). The research results illustrate that it provides a simple and efficient method for the direct detection of FQs in complex samples.

A restricted access molecularly imprinted polymer coating on metal-organic frameworks for solid-phase extraction of ofloxacin and enrofloxacin from bovine serum.

A restricted access molecularly imprinted polymer (RAMIP) crosslinked with bovine serum albumin (BSA) was prepared on the surface of the mesoporous UiO-66-NH2 metal-organic framework (MOF). The surface morphology, imprinting behavior, and protein exclusion properties of UiO-66-NH2@RAMIP@BSA were investigated. The maximum adsorption capacity was 50.55 mg g-1 for ofloxacin, with a 99.4% protein exclusion rate. Adsorption equilibrium was reached in 9 min. Combined with RP-HPLC, a solid-phase extraction column filled with UiO-66-NH2@RAMIP@BSA was used to selectively enrich and analyze ofloxacin and enrofloxacin antibiotics from bovine serum with recoveries of 93.7-104.2% with relative standard deviations of 2.0-4.5% (n = 3). The linear range and the limit of detection were 0.1-100 µg mL-1 and 15.6 ng mL-1, respectively. These results suggest that UiO-66-NH2@RAMIP@BSA is an efficient pretreatment adsorbent for biological sample analysis.

Preparation of Restricted Access Media-Molecularly Imprinted Polymers for the Detection of Chloramphenicol in Bovine Serum.

Chloramphenicol- (CAP-) restricted access media-molecularly imprinted polymers (CAP-RAM-MIPs) were prepared by precipitation polymerization using CAP as a template molecule, 2-diethylaminoethyl methacrylate (DEAEM) as a functional monomer, ethylene glycol dimethyl acrylate (EDMA) as a crosslinking agent, glycidyl methacrylate (GMA) as an outer hydrophilic functional monomer, and acetonitrile as a pore former and solvent. The CAP-RAM-MIPs were successfully characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The adsorption performance was investigated in detail using static, dynamic, and selective adsorption experiments. Adsorption equilibrium could be reached within 11 min. The CAP-RAM-MIPs had a high adsorption rate and good specific adsorption properties. Scatchard fitting curves indicated there were two binding sites for CAP-RAM-MIPs. Adsorption was Freundlich multilayer adsorption and consistent with the quasi-second kinetic model. Using CAP-RAM-MIPs for selective separation and enrichment CAP in bovine serum in combination with high-performance liquid chromatography (HPLC), CAP recovery ranged from 94.1 to 97.9% with relative standard deviations of 0.7-1.5%. This material has broad application prospects in enrichment and separation.

Dietary Lead Exposure and Associated Health Risks in Guangzhou, China.

Lead exposure is associated with a wide range of adverse effects on human health. The principal exposure route in the general population is through the diet. In this study, we estimate the dietary lead intake and associated health risks among the residents of Guangzhou, China. Data on lead concentrations were derived from the food safety risk monitoring system, which included 6339 samples from 27 food categories collected in 2014-2017. Food consumption data were taken from a 2011 dietary survey of 2960 Guangzhou residents from 998 households. Dietary lead intake was estimated by age group (3-6, 7-17, 18-59, and ≥60 years), and relevant health risks were assessed using the margin of exposure (MOE) method. The mean and 95th percentiles (P95) of dietary lead intake were respectively 0.7466 and 2.4525 µg/kg body weight per day for preschool children aged 3-6 years; 0.4739 and 1.5522 µg/kg bw/day for school children aged 7-17 years; 0.3759 and 1.1832 µg/kg bw/day for adults aged 18-59 years; and 0.4031 and 1.3589 µg/kg bw/day for adults aged ≥60 years. The MOE value was less than 1 for preschool children at the mean exposure level and for all age groups at the P95 exposure level. Rice and its products, leafy vegetables, and wheat flour and its products were found to be the primary food sources of lead exposure. Our findings suggest that the health risk from dietary lead exposure is low for Guangzhou residents overall, but that young children and consumers of certain foods may be at increased risk. Continued efforts are needed to reduce the dietary lead exposure in Guangzhou.

Both overexpression and suppression of an Oryza sativa NB-LRR-like gene OsLSR result in autoactivation of immune response and thiamine accumulation.

Tight and accurate regulation of immunity and thiamine biosynthesis is critical for proper defence mechanisms and several primary metabolic cycles in plants. Although thiamine is known to enhance plant defence by priming, the mechanism by which thiamine biosynthesis responds to immune signals remains poorly understood. Here we identified a novel rice (Oryza sativa L.) NB-LRR gene via an insertion mutation, this mutant confesses a low seed setting phenotype and the corresponding genetic locus was named OsLSR (Low seed setting related). Comparing with wildtype plant, both overexpression and suppression of OsLSR lead to the autoactivation of the rice immune system and accumulation of thiamine, which result in a great fitness cost and yield penalty. Moreover, when fused with eGFP at their C terminus, two fragments, OsLSR1-178 and OsLSR464-546, localized to chloroplasts where thiamine is produced. Our result suggests that OsLSR differs from traditional NB-LRR genes. Its expression is closely related to the immune status and thiamine level in plant cells and should be maintained within a narrow range for rice growth.